Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 241050

Area Forecast Discussion
National Weather Service Lincoln IL
550 AM CDT Thu Aug 24 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 322 AM CDT Thu Aug 24 2017

Not much of a shift in the forecast. Some mid level/sprinkles to
the NW running into a ridge and a very dry airmass per the 00Z ILX
sounding. Even the cu field may end up getting marginalized by the
dry column. Otherwise, mild day with light but increasingly
northeasterly winds. Tonight will be more of the same, and
depending on the dewpoints, may need to take another look at fog
as this morning is quite close with some patchy shallow ground fog
in low lying areas out there not getting picked up by ASOS.
Dewpoints to the west are a couple degrees higher, but the
northeasterly flow into the overnight will counter it. Xover temps
and a lack of cloud cover later this afternoon will provide better
confidence in any mention.

.LONG TERM...(Friday through Wednesday)
ISSUED AT 322 AM CDT Thu Aug 24 2017

Med and long range forecasts dominated by the surface ridge...the
next wave diving into the Midwest to wrap up Sunday and into the
work week...and the influence of Tropical Storm Harvey along the
Gulf Coast. Not much in the way to pull the tropical system off
of coastal TX and the wave diving into the Midwest is now treated
differently in both the GFS and the ECMWF. Both models are now
creating a cut off low...bringing in more of a front-like feature
for Monday...then slowing the upper low over the region, lingering
periodic pops into midweek. Interactions between the distant
tropical storm and the midlevels over the Ohio River
Valley/eastern trof have changed with each run. Overall
temperatures are mild with highs in the 70s/low 80s and the lows
in the 50s, pretty close to climatological norms on average. Best
chances for precip remain with the initial upper wave for Sun
night and into Monday. The impact of the pattern shift with the
cutoff low now over the region with the TS to the southwest is
causing some variability in the model runs. Should the low remain
anchored over the region, midweek could remain wet without impact
from TS Harvey.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 548 AM CDT Thu Aug 24 2017

VFR throughout, but added some mid/high scattered at about 15kft
as a wave to the northwest runs into the ridge axis. Between the
ridge and the dry air in place, sprinkles will be tough to come
by. A few limited cu later, collapsing before sunset. Increasingly
northeasterly winds becoming easterly late tonight.




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